In Revans' learning formula, L = P + Q, Q represents "questioning insight", by which Revans means that insight comes out of the process of questioning programmed knowledge (P) in the light of experience. We typically focus on the content of an insight rather than on the act of insight. Drawing primarily on the work of Bernard Lonergan this paper discusses the act of insight and explores insight's place in the operations of human knowing and shows how it is at the heart of action learning. (Contains 1 table.)